1. Field of the Invention
The present invention provides a portable communication device which is compact, right-weight, inexpensive and highly reliable and can protect a printed circuit board and electronic part from an impact or an external pressure without using a highly rigid material for a housing.
2. Description of the Relate Art
The portable communication device represented by the portable telephones is being made smaller and lighter in weight to improve portability recently.
However, there is a drawback in strength because a housing, a printed circuit board and the like are made thinner as the device is made smaller and lighter.
To solve such an issue, Japanese Utility Model Application Laid-Open Publication (Kokai) No. Showa 62-124897 proposes a structure to enhance strength of the housing in that a printed circuit board can be made thinner without requiring the printed circuit board to have high strength and can be held finely without warping.
FIG. 8 is a sectional view of a casing to show a structure of the technology disclosed in the aforesaid Japanese Utility Model Application Laid-Open Publication (Kokai) No. Showa 62-124897.
It is seen that a metallic shielding plate 102 is disposed on the back side of a printed circuit board 101, and the metallic shielding plate 102 and the printed circuit board 101 are fixed to a device casing 103 by means of screws 104.
By configuring as described above, the printed circuit board 101 can be made thin without requiring the printed circuit board 101 to have high strength and be held finely without being warped, and the housing can be improved to have high strength.
Furthermore, Japanese Utility Model Application Laid-Open Publication (Kokai) No. Heisei 05-078042 proposes a structure to protect electronic parts having low structural strength by disposing an electronic part having a larger size and higher structural strength on both sides of and close to the electronic parts having lower structural strength, or by disposing an electronic part having a larger size and higher structural strength on both sides of and close to the electronic parts having lower structural strength and forming a recess on the inside surface of the housing at a position corresponding to each electronic part having lower structural strength in order to accommodate the electronic parts having lower structural strength, to prevent any part of the housing from contacting to the electronic parts having low strength in case of application of an external pressure to the housing.
FIG. 9 and FIG. 10 are sectional views of the casing to show the structure of the technology disclosed in the aforesaid Japanese Utility Model Application Laid-Open Publication (Kokai) No. Heisei 05-078042.
FIG. 9 shows that in a compact electronic instrument which accommodates a plurality of electronic parts for configuring an electronic circuit in a housing 201, electronic parts 202, 202 having a larger size and higher structural strength are disposed on both sides of and close to an electronic part 203 having lower structural strength among the aforesaid multiple electronic parts.
In the structure shown in FIG. 10, when the electronic part 203 having lower structural strength is high in height, the electronic parts 202, 202 having a larger size and higher structural strength are disposed on both sides of and close to the electronic part 203, and a recess 204 is formed on the inside wall of the housing 201 to which the electronic part 203 is opposed. The electronic parts with low structural strength can be protected by configuring as described above.
However, the structure disclosed in the aforesaid Japanese Utility Model Application Laid-Open Publication No. Showa 62-124897 has disadvantages of having an increase in thickness and weight due to the use of the metallic shielding plate, and an increase in costs due to an increase in the number of parts and the like.
The structure disclosed in the aforesaid Japanese Utility Model Application Laid-Open Publication No. Heisei 05-078042 has a disadvantage that full protection of the electronic parts cannot be made though the electronic parts having low structural strength can be protected.
To remedy the aforesaid disadvantages of the prior art, it is an object of the present invention to provide an assembly structure of a housing for a portable communication device which is compact, light in weight, inexpensive and highly reliable and can protect a printed circuit board and electronic parts from an impact or an external pressure without using a highly rigid material for the housing.
According to one aspect of the invention, a portable communication device having a key operation section, a display, a mouthpiece and a receiver on a housing consisting of an upper casing and a lower casing, comprises
a plurality of projections formed on one or both of the upper casing and the lower casing,
a plurality of through holes formed on at least a printed circuit board, on which various types of electronic parts are mounted, housed in the housing so to allow the projections to pierce through the holes,
wherein the projections designed to pierce through the through holes of the printed circuit board to fix the printed circuit board between the upper casing and the lower casing.
In the preferred construction, a plurality of holes are formed on the key operation section in the form of a sheet housed in the housing to allow the projections to pierce through the holes.
In another preferred construction, the projections formed on the upper casing are pierced through the through holes of the printed circuit board, and fixing screws are screwed into the projections through holes formed on the lower casing at positions where the leading ends of the projections come into contact so to integrate the upper casing and the lower casing into one body to fix the printed circuit board between the upper casing and the lower casing.
In another preferred construction, the projections formed on the lower casing are pierced through the through holes of the printed circuit board, and fixing screws are screwed into the projections through holes formed on the upper casing at positions where the leading ends of the projections come into contact so to integrate the upper casing and the lower casing into one body to fix the printed circuit board between the upper casing and the lower casing.
In another preferred construction, the projections formed on the upper casing and the lower casing are pierced through the holes formed on the printed circuit board, and protrusions formed on the leading ends of the projections on either of the upper casing or the lower casing are inserted into recesses formed on the leading ends of the projections of the other casing so to integrate the upper casing and the lower casing into one body to fix the printed circuit board between the upper casing and the lower casing.
In another preferred construction, the projections formed on the upper casing and the lower casing are pierced through the holes formed on the printed circuit board, and fixing screws inserted from recesses formed in the projections of either of the upper casing or the lower casing are screwed into the leading ends of the projections of the other casing to integrate the upper casing and the lower casing into one body to fix the printed circuit board between the upper casing and the lower casing.
In another preferred construction, holes are formed on the casing to allow the projections to pierce through the holes, the projections formed on the upper casing are pierced through the through holes of the printed circuit board and also the holes of the lower casing, and fixing screws are screwed into the projections from the outside of the holes of the lower casing to integrate the upper casing and the lower casing into one body so to fix the printed circuit board between the upper casing and the lower casing.
Preferably, the structure is applied to a portable telephone.
Other objects, features and advantages of the present invention will become clear from the detailed description given herebelow.